1. Field
Exemplary embodiments of the present invention relate to a light scanning unit and an image forming apparatus including the light scanning unit, and more particularly, to a light scanning unit having an improved installation structure of a reflection member, and an image forming apparatus including the light scanning unit.
2. Description of the Related Art
An electrophotographic image forming apparatus such as a laser printer, a digital copier, a multifunctional printer (MFP), etc. has a structure in which a light beam may be scanned onto an image holding body through a light scanning unit so as to form an electrostatic latent image. The electrostatic latent image is developed into a developed image by using a developer such as toner, and the developed image is transferred to a print medium.
To produce a color image in the image forming apparatus, a light beam may be scanned onto each of image holding bodies corresponding to different colors. An electrostatic latent image formed on each image holding body is developed by using toner of different colors, and developed images of different colors are transferred to a single print medium. The light scanning unit can be made compact by an oblique incidence method using a single optical deflector. According to an oblique incidence type light scanning unit, to guide a light beam that has been scanned by an optical deflector toward each image holding body corresponding to an individual color, a plurality of light beams are obliquely incident upon a deflection surface that is perpendicular to a rotational axis of an optical deflector, and then a luminous flux is split.
The oblique incidence type light scanning unit has an advantageous structure in reducing material costs due to a compact optical path layout and a reduced number of parts. In order to have light beams scanned at appropriate positions in the light scanning unit, a reflection mirror may be arranged on an optical path of each light beam. In the light scanning unit, when an imaging lens is arranged at a position close to a to-be-scanned surface of an image holding body and the reflection mirror is arranged between the optical deflector and the imaging lens, a placement angle causes a change of the position of a light beam scanned onto the imaging lens, sensitively affecting the curvature of a scanning line. In an attempt to address the above issue, in a conventional light scanning unit, an adjustment member for correcting the curvature of a scanning line may be provided on a reflection mirror holder. Thus, when a reflection mirror is coupled to a housing of a light scanning unit, the reflection mirror is fixed after a placement angle of the reflection mirror is adjusted by using the adjustment member.
However, conventional light scanning units have problems in that material costs are increased as a separate adjustment member may be added to adjust the placement angle of a reflection mirror, and productivity is degraded as an adjustment process is added for mass production. In addition, in a conventional light scanning unit, a pressure direction of the adjustment member for adjusting the placement angle of a reflection mirror of a holder for fixing the reflection mirror may be designed to change a scanning line curvature characteristic in the same direction. Accordingly, when a print operation is continuously performed and thus the temperature of an interior of an image forming apparatus increases, a holder that fixes the reflection mirror is thermally deformed and thus a placement surface of the reflection mirror collapses to incline. As a result, the scanning line curvature characteristic is adversely affected.